Iatrogenic interruption of the myocardial conduction system.
Explore the source record for details and available documents.
Biomedical subjects
Publications and source records attributed to R C Truex.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
This report concerns a four-month-old white female infant who exhibited abnormal feeding behavior and EKG irregularities during a newborn sucking behavior study. The immediate post-birth history showed an irregular heart rate on two occasions, but a cardiac consultation elicited no unusual findings. During sucrose sucking conditions, the heart rate increased with a beat-to-beat variation of 50 beats per minute, noted to be due to premature atrial beats. At 39 days, an EKG showed a marked sinus tachycardia of 156, a PR interval of 0.08, QRS of 0.05 and a QT of 0.26. The infant was diagnosed as a sudden infant death syndrome (SIDS) following an unexpected death at home. Subsequent cardiac pathology revealed an anomalous tract between the right atrium and the atrioventricular (AV) bundle which formed an extensive bypass of the AV node (atrio-His tract), and two accessory AV connections between the left atrium and posterior left ventricle. These findings are consistent with the Wolff-Parkinson-White syndrome type A. Only further studies can determine whether such abnormal feeding behavior with EKG irregularities can be used to identify infants who are at high risk for sudden death.
The hypercarbia stimulation test is a valuable technique to document the absence of brainstem responsiveness to elevated levels of carbon dioxide (PCO2); however, its application has been limited by concern that hypoxemia may induce cardiovascular instability. We investigated hemodynamic and oxygen (PO2) changes in 19 patients: group 1 (17 patients) had no spontaneous ventilations at PCO2 values ranging from 37-129 torr; group 2 (2 patients) had spontaneous ventilations at less than 38 torr. Group 1 was separated into 2 subgroups: A (10 patients) with PO2 greater than 153 torr and B (7 patients) with PO2 less than 80 torr. Hemodynamic changes (less than 10% variation in baseline pulse and blood pressure) occurred in 9 of 10 patients in group 1A and all patients in Group 1B. Mean differences in pulse and blood pressure changes between these groups were not significant; therefore, pulse and blood pressure changes are not predictive of hypoxemia and hypercarbia is not necessary to induce spontaneous ventilation in patients with intact medullary function.
Explore the source record for details and available documents.
When a cystic structure in the posterior fossa increases in size, the accompanying increase in pressure may cause it to herniate upward through the tentorial hiatus. In our experience this happens most commonly with a dilated trapped fourth ventricle secondary to infection or intraventricular hemorrhage. However, herniation of an arachnoid cyst or a Dandy-Walker malformation through the tentorium may also occur. When herniation occurs, the cystic structure assumes a "keyhole" configuration, indicating that it is trapped and that surgical intervention is necessary. Five cases are presented that illustrate this point, including two patients with dilatation of the fourth ventricle secondary to hemorrhage, two patients with Dandy-Walker malformation, and one patient with an arachnoid cyst.